What is the Hardest Wood on Earth?

Trivia for wood lovers. There is some hard wood out there, people. April 11, 2008

Question
I have a small piece of African ebony left from when I bought some about fifteen years ago. It's the solid black specie, not the striped black specie. I'm curious to know if it is the hardest, densest wood on the planet, or if some other species are just as hard and dense, or perhaps even harder and denser.

Forum Responses
From Professor Gene Wengert, Sawing and Drying Forum technical advisor:
Of the commercial timbers, lignum vitae is the heaviest, which is over 15% heavier than ebony.

Here is a quote from a US Forest Products Lab publication dated 1969...

"The most important and exacting use of lignum vitae is for bearings or bushing blocks lining the stern tubes of propeller shafts of steamships and submarines. The blocks are machined to conform to the curvature of the propeller shaft on one end-grain surface, and on the other side to conform to the curvature of the propeller tube. Numerous attempts have been made to substitute other hard, heavy woods for use as underwater bearings but none contain the high guaiac resin content which makes lignum vitae self lubricating and unique for this very exacting utilization."

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From contributor A:
I read somewhere that some Bulnesia arborea from northern Venezuela and Colombia can be harder and heavier than Lignum. There are at least two sorts of Lignum, called ''male'' and ''female'' Lignum, female being lighter than male, I think. G. sanctum and G. oficinale.

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From contributor V:
Takeshi Okuma, librarian at Camp Courtney, Okinawa, claims that the hardest wood in the world is Tiga, found in Sibuyan Island, Philippines. This island is reputed to have more indigenous flora and fauna than what Darwin found in the Galapagos.